Hot foods, particularly hot liquids, are commonly served and consumed in disposable containers. These containers are made from a variety of materials including paperboard and foamed polymeric sheet material. One of the least expensive sources of paperboard material is cellulose fibers. Cellulose fibers are employed to produce excellent paperboards for the production of hot cups, paper plates, and other food and beverage containers. Conventional paperboard produced from cellulosic fibers, however, is relatively dense, and therefore, transmits heat more readily than, for example, foamed polymeric sheet material. Thus, hot liquids are typically served in double cups or in cups containing multiple plies of conventional paperboard.
It is desirable to possess an insulating paperboard produced from cellulosic material that has good insulating characteristics, that will allow the user to sense that food in the container is warm or hot and at the same time will allow the consumer of the food or beverage in the container to hold the container for a lengthy period of time without the sensation of excessive temperature. It is further desirable to provide an insulating paperboard that can be tailored to provide a variety of insulating characteristics so that the temperature drop across the paperboard can be adjusted for a particular end use.